A Solution to Remote Detection of Illegal Electricity.doc
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Power line communication (PLC) presents an interesting and economical solution for Automatic Meter Reading (AMR). If an AMR system via PLC is set in a power delivery system, a detection system for illegal electricity usage may be easily added in the existing PLC network. In the detection system, the second digitally energy meter chip is used and the value of energy is stored. The recorded energy is compared with the value at the main kilo Watt-hour meter. In the case of the difference between two recorded energy data, an error signal is generated and transmitted via PLC network. The detector and control system is proposed. The architecture of the system and their critical components are given. The measurement results are given.
This paper describes detector system for illegal electricity usage using the power lines based on the research work-taking place at the Central Power Research Institute (CPRI), Bangalore. The target of this study is to discover new and possible solutions for this problem.
1. INTRODUCTION :
India, the largest democracy with an estimated population of about 1.04 billion, is on a road to rapid growth in economy. Energy, particularly electricity, is a key input for accelerating economic growth. The theft of electricity is a criminal offence and power utilities are losing billions of rupees in this account. If an Automatic Meter Reading system via Power line Communication is set in a power delivery system, a detection system for illegal electricity usage is possible .Power line communications (PLC) has many new service possibilities on the data transferring via power lines without use of extra cables. Automatic Meter Reading (AMR) is a very important application in these possibilities due to every user connected each other via modems, using power lines. AMR is a technique to facilitate remote readings of energy consumption.
The following sections will describe the proposed detection and control system for illegal electricity usage using the power lines. The scheme is based on the research work-taking place at “Central Power Research Unit (CPRI), Bangalore ”.In this section the discussion is on how a subscriber can illegally use the electricity and the basic building blocks for the detection using power line communication.
Methods of illegal electricity usage:
In illegal usage a subscriber illegally use electricity in the following ways,
1) Using the mechanical objects: A subscriber can use some mechanical objects to prevent the revolution of a meter, so that disk speed is reduced and the recorded energy is also reduced.
2) Using a fixed magnet: A subscriber can use a fixed magnet to change the electromagnetic field of the current coils. As is well known, the recorded energy is proportional to electromagnetic field.
3) Using the external phase before meter terminals: This method gives subscribers free energy without any record.
4) Switching the energy cables at the meter connector box: In this way, the current does not pass through the current coil of the meter, so the meter does not record the energy consumption.
Although all of the methods explained above may be valid for electromechanical meters, only the last two methods are valid for digital meters. Therefore, this problem should be solved by electronics and control techniques .
2 BUILDING BLOCKS FOR DETECTION:
2.1. Automatic Meter Reading (AMR):
The AMR system starts at the meter. Some means of translating readings from rotating meter dials, or cyclometer style meter dials, into digital form is necessary in order to send digital metering data from the customer site to a central point.
In most cases, the meter that is used in an AMR system is the same ordinary meter used for manual reading but the difference with conventional energy meter is the addition of some device to generate pulses relating to the amount of consumption monitored, or generates an electronic, digital code that translates to the actual reading on the meter dials. One such technique using optical sensor is shown in above fig……
Three main components of AMR system are:
1. Meter interface module: with power supply, meter sensors, controlling electronics and a communication interface that allows data to be transmitted from this remote device to a central location.
2. Communications systems: used for the transmission, or telemetry, of data and control send signals between the meter interface units and the central office.
3. Central office systems equipment: including modems, receivers, data concentrators, controllers, host upload links, and host computer .
2.2 POWER LINE COMMUNICATION (PLC):
Power line carrier communications take place over the same lines that deliver electricity. This technique involves injecting a high frequency AC carrier onto the power line and modulating this carrier with data originating from the remote meter or central station. Power line communications has many new service possibilities on the data transferring via power lines without use of extra cables. AMR is a very important application in these possibilities due to every user connected each other via power lines. In this power network, every user connected to each other via modems with data originating from the remote meter or central station. Electrical power systems vary in configuration from country to country depending on the state of the respective power sources and loads. The practice of using medium-voltage (11-to-33kV) and low-voltage (100-to-400V) power distribution lines as high-speed PLC communication means and optical networks as backbone networks is commonplace.Under normal service conditions, they can be broadly divided into open-loop systems, each with a single opening, and tree systems with radial arranged lines. In the case of tree systems, connection points for adjacent systems are provided in order that paths/loads may be switched when necessary for operation. Additionally, in terms of distribution line types, there are underground cables and overhead power distribution lines. Where transformers are concerned, they can be divided into pole-mounted transformers, pad-mounted transformers and indoor transformers.